Republican U.S. Senate candidate Joni Ernst and her husband Gail, rear, fill out their ballots in Iowa’s Republican primary in Red Oak, Iowa, Tuesday, June 3, 2014. Five Republicans are competing for the GOP Senate nomination and a chance to face Democrat Bruce Braley, who is running unopposed. AP

Republican U.S. Senate candidate Joni Ernst and her husband Gail, rear, fill out their ballots in Iowa’s Republican primary in Red Oak, Iowa, Tuesday, June 3, 2014. Five Republicans are competing for the GOP Senate nomination and a chance to face Democrat Bruce Braley, who is running unopposed. AP

Can Republicans pick up Iowa Senate seat?

While most election-watchers Tuesday will be focused on whether Sen. Thad Cochran, R-Miss., survives his primary, Iowa could be a big deal. Republicans see a good chance of picking up a Senate seat there this year, as Sen. Tom Harkin, D-Iowa, is retiring.

Republican Joni Ernst is a big favorite not only of the Republican establishment, but many tea party forces. The latest Des Moines Register poll, taken May 27 to 30, showed the “mother, solider, conservative” with twice as much support as her closest rival.

But Ernst’s total was 36 percent, barely above the 35 percent she would need for outright victory. If she doesn’t hit the 35 percent mark, the nomination goes to a state convention June 14.

Ernst, an Iraq war veteran, is seen as having momentum.

“The poll shows Ernst's lead is significant across all demographics, factions and geographies,” wrote the Register’s Jennifer Jacobs. “She does well with both men and women, with every age group, with the tea party and born-again Christians and with voters in every congressional district, including the 4th, Iowa's most conservative district.”